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We assessed natural regeneration of longleaf pine (Pinus palustris Mill.) using the data collected from the Escambia Experimental Forest in southern Alabama. Fifteen years after the regeneration control, natural regeneration of longleaf pine remained patchy across a wide range of site and stand conditions; slightly more than half of all plots contained regeneration, but the density of seedlings and saplings varied significantly. The abundance of seedlings [less than or equal to] 1- year-old was positively related to stand age and time since last fire, but negatively related to overstory basal area. The abundance of seedlings and saplings was positively related to stand age, but negatively related to time since last fire and overstory basal area. The probability of achieving at least 15 000 seedlings * [ha.sup.-1] that are older than 1 year but less than 1 m tall and at least 1250 saplings * [ha.sup.-1] that are over 1 m tall was, respectively, positively related to the ratio of time since last fire to overstory basal area and the ratio of quadratic mean diameter to site index. A longer fire interval (> 2 to 3 years) should be adopted to naturally regenerate longleaf. We did not find clear zones of exclusion present in natural regeneration even though overstory trees, seedlings, and saplings tended to be repulsive spatially and >80% grass stage seedlings and saplings occurred outside tree crowns. Key words: longleaf pine (Pinus palustris Mill.), natural regeneration, zero- inflated negative binomial model, point pattern data, spatial analysis. Nous avons evalue la regeneration naturelle du pin des marais (Pinus palustris Mill.) en utilisant les donnees recueillies dans la Foret experimentale d'Escambia situee dans le sud de l'Alabama. Quinze ans apres une inspection de la regeneration, la regeneration naturelle du pin des marais etait restee irreguliere malgre une large gamme de conditions de station et de peuplements; un peu plus de la moitie des placettes etaient regenerees, mais la densite des semis et des gaules variait considerablement. L'abondance des semis de moins d'un an etait positivement liee a l'age du peuplement et au temps ecoule depuis le dernier feu, mais negativement liee a la surface terriere du couvert dominant. L'abondance des semis et des gaules etait positivement liee a l'age du peuplement, mais negativement liee au temps ecoule depuis le dernier feu et a la surface terriere du couvert dominant. La probabilite d'obtenir au moins 15 000 semis * [ha.sup.-1] plus vieux qu'un an mais d'une hauteur egale ou inferieure a 1 m, et au moins 1250 gaules * [ha.sup.-1] d'une hauteur superieure a 1 m etait, respectivement, positivement correlee au rapport entre le temps ecoule depuis le dernier feu et la surface terriere du couvert dominant et au rapport entre le diametre quadratique moyen et l'indice de qualite de station. Un intervalle de feu plus long (plus de 2 a 3 ans) devrait etre adopte pour regenerer naturellement le pin des marais. Nous n'avons pas trouve de zones claires d'exclusion de la regeneration naturelle meme si les arbres du couvert dominant, les semis et les gaules avaient tendance a etre spatialement repulsifs et que plus de 80 % des petits semis et des gaules etaient etablis hors de la projection de la cime des arbres. [Traduit par la Redaction] Mots-cles: pin des marais (Pinus palustris Mill.), regeneration naturelle, modele binomial negatif a exces de zero, donnees par patron de points, analyse spatiale., Introduction The longleaf pine (Pinus palustris Mill.) forest ecosystem in the southern United States is a unique ecological community that has experienced a drastic reduction in area, from approximately 37.2 [...]

Trees in dry forests often regenerate in episodic pulses when wet periods coincide with ample seed production. Factors leading to success or failure of regeneration pulses are poorly understood. We investigated the impacts of stand thinning on survival and growth of the 2013 cohort of ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) seedlings in northern Arizona, United States. We measured seedling survival and growth over the first five growing seasons after germination in six stand basal areas (BAs; 0, 7, 14, 23, 34, and 66 (unthinned) [m.sup.2]*[ha.sup.-1]) produced by long-term experimental thinnings. Five-year survival averaged 2.5% and varied among BAs. Mean survival duration was longer in intermediate BAs (11 to 16 months) than in clearings and high BAs (5 months). The BAs of 7, 14, and 23 [m.sup.2]*[ha.sup.-1] had >2600 5-year-old seedlings*[ha.sup.-1]. In contrast, regeneration was lower in the clearing (666 seedlings*[ha.sup.-1]) and failed completely in the 34[m.sup.2]*[ha.sup.-1] and unthinned treatments. Seedling survival was highest during wet years and lowest during drought years. Many surviving seedlings had no net height growth between years 4 and 5 because of stem browsing. Results indicate that natural regeneration of ponderosa pine is influenced by stand BA, drought, herbivory, and interactions between extreme climatic events. Key words: Pinus ponderosa, thinning, tree seedling establishment, seedling mortality, stand management. Les arbres des forets seches se regenerent souvent en vagues episodiques lorsque des periodes humides coincident avec une production abondante de graines. On connait mal les facteurs responsables du succes ou de l'echec des vagues de regeneration. Nous avons etudie les effets de l'eclaircie des peuplements sur la survie et la croissance de la cohorte de semis de pin ponderosa (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) etablie en 2013 dans le nord de l'Arizona, aux Etats-Unis. Nous avons mesure la survie et la croissance des semis au cours des cinq premieres saisons de croissance apres leur germination en fonction de six classes de surface terriere (0, 7, 14, 23, 34 et 66 (non eclairci)[m.sup.2]*[ha.sup.-1]) provenant d'un dispositif experimental suivi a long terme. Le taux de survie a 5 ans etait en moyenne de 2,5 % et variait selon la surface terriere. La duree de survie moyenne etait plus longue pour les surfaces terrieres intermediaires (11 a 15 mois) que dans les zones coupees a blanc et celles oU la surface terriere etait elevee (5 mois). Les surfaces terrieres de 7, 14 et 23 [m.sup.2]*[ha.sup.-1] avaient plus de 2600 semis-ha-1 ages de 5 ans. En revanche, la regeneration etait plus faible dans les zones coupees a blanc (666 semis*[ha.sup.-1]) et etait completement absente dans le traitement a 34 [m.sup.2]*[ha.sup.-1] et les zones non eclaircies. La survie des semis etait la plus elevee pendant les annees humides et la plus faible pendant les annees de secheresse. La croissance nette en hauteur de nombreux semis survivants a ete nulle entre la quatrieme et la cinquieme annee en raison du broutement. Les resultats indiquent que la regeneration naturelle du pin ponderosa est influencee par la surface terriere du peuplement, la secheresse, l'herbivorisme et les interactions entre les evenements climatiques extremes. [Traduit par la Redaction] Mots-cles: Pinus ponderosa, eclaircie, etablissement des semis, mortalite des semis, amenagement des peuplements., Introduction Many coniferous forests of western North America are experiencing large-scale mortality of mature trees from drought, wildfire, and bark beetle (Dendroctonus ponderosae Hopkins, 1902) attacks (Cohen et al. 2016; [...]

In the latest literature, climate models show that the conditions for pines, spruces, larches, and birches will deteriorate significantly. In Poland, as well as in other European countries, there are already signs of the decline of these species. This review article deals with the symbiotic relationships between fungi and plants, which can hardly be overestimated, using the example of pine trees. These are the oldest known symbiotic relationships, which are of great benefit to both components and can help plants, in particular, survive periods of severe drought and the attack of pathogens on the roots. This article describes symbioses and their causal conditions, as well as the mycorrhizal components of pine trees and their properties; characterizes ectomycorrhizal fungi and their mushroom-forming properties; and provides examples of the cultivation of pure fungal cultures, with particular attention to the specificity of the mycorrhizal structure and its effects on the growth and development of Pinus species. Finally, the role of mycorrhiza in plant protection and pathogen control is described. [ABSTRACT FROM AUTHOR]

Abstract: Forest structural diversity was estimated for an ecological province in the north-central region of the United States of America using data for nearly 350 000 trees observed on >12 [...]

Background Black locust (BL, Robinia pseudoacacia) is considered a promising tree species for reforestation due to its great ability to fix nitrogen. However, after two or three coppice-harvesting rotations, the productivity of BL declines. Whether soil microbial communities are affected and how these groups correlate with the nitrogen mineralization process across multi-generation stands remains unclear. Methods We investigated the composition and structure of free-living nitrogen-fixing microorganisms (diazotrophs) by sequencing the marker gene nifH and compared these results to levels of soil nitrogen mineralization in the bulk soil and rhizosphere in black locust plantations on Mount Tai, China. Results The results showed multi-generation BL coppice plantations decreased the total soil nitrogen (N), soil phosphorus (P), soil microbial biomass N (MBN), soil microbial biomass C (MBC), soil nitrification rate (Rn), soil ammonification rate (Ra), and net soil N mineralization rate (Rm), but significantly increased the concentration of soil NH4+-N to maintain sufficient NO3−-N. The dominant species in bulk soil and rhizosphere changed from Rhodopseudomonas (22.62% and 15.76%), unclassified_c_Alphaproteobacteria (22.37% and 29.28%), unclassified_o_Rhizobiales (15.40% and 13.31%), Bradyrhizobium (12.00% and 11.74%) in seedling plantations to Bradyrhizobium (45.95% and 47.86%) and Rhodopseudomonas (43.56% and 41.84%) in coppice plantations, respectively. Mantel test and Redundancy analysis (RDA) revealed that Rn, Ra, and Rm were the most important factors shaping the diazotrophic communities. Conclusions Our results suggest that the multi-generation BL coppice plantation can homogenize soil diazotrophic communities, which is mainly regulated by the available N loss caused by nitrogen mineralization. Strengthening the management technology of coppice plantations will provide more beneficial external consumption. [ABSTRACT FROM AUTHOR]

Quantifying invasion severity of nonnative invasive plant species is vital for the development of appropriate mitigation and control measures. We examined more than 23,250 Forest Inventory and Analysis (FIA) plots from the southern coastal states of the United States to develop an alternative method to classify and map the invasion severity of Chinese tallow (Triadica sebifera). Remeasured FIA plot-level data were used to examine the spatiotemporal changes in the presence probability and cover percentage of tallow. Four invasion severity classes were identified by using the product of presence probability and cover percentage. Chinese tallow invasion severity increased over time with 90 and 123 counties being classified into the highest severity class for the first and second measurement, respectively. Further, the invasibility of major forest-type groups by severity class was examined using the product of the county-level mean presence probability and mean cover percentage of Chinese tallow as a proxy of invasibility. Longleaf/slash pine (Pinus palustris/P. elliottii) forests were highly resilient to the Chinese tallow invasion. In contrast, elm/ash/cottonwood (Ulmus spp./Fraxinus spp./Populus deltoides) and oak/gum/cypress (Quercus spp./Nyssa spp./Taxodium spp.) forest-type groups were vulnerable to invasion. [ABSTRACT FROM AUTHOR]

The Levels-of-Growing-Stock study for ponderosa pine was a collective effort among western Research Stations within the US Forest Service. The experiment was established to test sustainable productivity across a wide range of densities by periodically thinning the plots. Beyond the original purposes for wood production, contemporary applications of these long-term studies have been to determine stand density effects on (i) both overstory and understory responses to stand development of even-aged ponderosa pine, (ii) biomass accumulation and carbon sequestration, (iii) plant diversity and wildlife habitats, and (iv) forest resiliency to insects and pathogens, droughts, and wildfires. Furthermore, these installations have served as a showpiece for the public and natural laboratories for professional foresters and students. For the past half century, the study has helped guide land managers and stakeholders on public and private lands about the value of thinning in overstocked young stands of ponderosa pine across its range. We hope that it will continue to serve as a springboard for addressing future issues facing forest management. [ABSTRACT FROM AUTHOR]

In ancient times, human beings believed that the sun revolved around the Earth. Copernicus and Galileo, among others, demonstrated that the opposite was true, that the Earth actually revolved around [...]

We used non-native invasive plant data from the US Forest Service’s Forest Inventory and Analysis (FIA) program, spatial statistical methods, and the space (cover class)-for-time approach to quantify the invasion potential and success (“invasibility”) of three major invasive shrubs (multiflora rose, non-native bush honeysuckles, and common buckthorn) in broadly classified forest-type groups in seven Upper Midwest states. Smoothed maps of presence and cover percent showed a strong clustering pattern for all three invasive shrubs despite their different ranges. The species are clustered around major cities or urban areas (e.g., Chicago, Illinois, and Des Moines, Iowa), indicating the potential role humans played in their invasion and spread on the landscape and throughout the Midwest. Conditional inference tree (ctree) models further quantified the significant factors contributing to the observed regional patterns: for distribution of multiflora rose, percentage of forest cover in the county (measuring human disturbance intensity) and stand density index; for distribution of common buckthorn, distance to major highways. Non-native bush honeysuckles were not associated with any disturbance and site/stand variables except for latitude and longitude. The infested FIA plots by cover class were positively associated in space, signifying a concentric-like spread trend from previously infested sites (hot spots) to surrounding areas. By forest-type groups or as a whole, the three species spread slowly at earlier stages, but recently have increased significantly in presence/expansion. Oak/hickory and elm/ash/cottonwood forests were more susceptible to the three invasive shrubs compared to other forests. We recommend that resource managers and planners prescribe control and mitigation treatments for non-native invasive plants by forest types and spatial locations close to highways and residences. [ABSTRACT FROM AUTHOR]

The future of ponderosa pine ( Pinus ponderosa var. scopulorum ) forests in the southwestern United States is uncertain because climate-change-induced stresses are expected to increase tree mortality and place greater constraints on regeneration. Silvicultural treatments, which include thinning, are increasingly being used to address forest health concerns by restoring ponderosa pine forests to more open conditions representative of historical forest structure. In light of the greater use of thinning and mounting concerns about the future of the species at the southern edge of its range, further investigations about impacts of thinning on ponderosa pine regeneration and underlying mechanisms are needed. We used a long-term (>50 years) experiment in northern Arizona to investigate impacts of repeated stand thinning that maintained different growing stock basal areas (0, 7, 14, 23, 34, 66 m 2 ha −1 ) on early seedling survival, growth, and microenvironment. Seedling survival for the first two years after germination (2013–2015), which had above-average precipitation, was higher than reported in several earlier studies and ranged between 4 and 21% among all basal areas. Seedling density exhibited a negative quadratic relationship with basal area and was positively associated with litter cover. Growing stock levels that fostered the highest seedling survival and density were those with a low density of overstory trees, low canopy cover, high cone production, coverage of soil by a thin layer of litter, and high soil water content at a depth of 15–30 cm. Overstory basal area was positively associated with seedling height but negatively associated with seedling diameter. During this relatively wet period, all basal area treatments supported higher average seedling densities than those previously recommended to produce a multi-aged stand or presettlement structure in the southwestern United States. Our results show that long-term maintenance of low to intermediate basal areas (7–23 m 2 ha −1 ) by thinning over the last 50 years led to a favorable microenvironment for early seedling establishment of ponderosa pine. [ABSTRACT FROM AUTHOR]

In two hemiboreal mixed spruce–hardwood forests in north-east Estonia, we studied (1) which factors affect tree regeneration survival and development during the first post-storm decade and (2) how these effects change in time. Regeneration height and mortality of the tree species black alder ( Alnus glutinosa (L.) J. Gaertn.), birch ( Betula pendula Roth., Betula pubescens Ehrh.), Norway spruce ( Picea abies (L.) Karst.) and European rowan ( Sorbus aucuparia L.) were analysed in moderately and heavily damaged stands, in two types of windstorm-created microsites, i.e. root-plate pits and mounds of uprooted trees, and on intact soil at different stages since disturbance. Regeneration was significantly taller in heavily damaged areas and species traits regarding tree height only became noteworthy at later stages since disturbance. Mortality probability was initially indifferent to microsite type and increased later for regeneration on intact soil compared to regeneration on the storm-induced microsites. Mortality increased with storm severity for A . glutinosa and Betula , whereas mortality of P . abies was initially low and became higher with time since disturbance in areas with increased levels of coarse woody debris. Eventually, height and height increment in previous years were clearly negatively related to mortality probability and competition levels in previous years increased chance of death. The relatively high spatial heterogeneity and trends in dominance of post-storm microsites by different tree species increase disturbance-emulating management options. In conclusion, regeneration mortality and species composition are initially directed by exogenous factors linked to storm severity and microsite heterogeneity, generating a degree of spatial partitioning within a microsite, whereas gradually species’ life-history traits and competition take over. [ABSTRACT FROM AUTHOR]

The Northern United States includes the 20 states bounded by Maine, Maryland, Missouri, and Minnesota. With 70 million ha of forestland and 124 million people, it is the most densely forested (42% of land area) and most densely populated (74 people/km2) quadrant of the United States. Three recent, large-scale, multiresource assessments of forest conditions provide insight about trends and issues in the North, and collectively these and other supporting documents highlight factors that will be extraordinarily influential in large-scale northern forest management needs over the next 50 years. This review article discusses five of those factors: (1 ) northern forests lack age-class diversity and will uniformly grow old without management interventions or natural disturbances, (2 ) the area of forestland in the North will decrease as a consequence of expanding urban areas, (3 ) invasive species will alter forest density, diversity, and function, (4 ) management intensity for timber is low in northern forests and likely to remain so, and (5) management for nontimber objectives will gain relevance but will be challenging to implement. Suggested actions to address these factors include the following: develop quantifiable state and regional goals for forest diversity, understand the spatial and structural impacts of urban expansion on forests, develop symbiotic relationships among forest owners, forest managers, forest industry and the other stakeholders to support contemporary conservation goals, and work to understand the many dimensions of forest change. In the next several decades, climate change seems unlikely to overwhelm or negate any of the five factors discussed in this article; rather it will add another complicating dimension. [ABSTRACT FROM AUTHOR]

Nonnative invasive plants (IPs) are rapidly spreading into natural ecosystems (e.g., forests and grasslands). Potential threats of IP invasion into natural ecosystems include biodiversity loss, structural and environmental change, habitat degradation, and economic losses. The Upper Midwest of the United States encompasses the states of Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, and Wisconsin, a region populated with 46 million people. Concerns of IP threats to the productive timberlands in the region have emerged with rapid expansion of urban areas and associated land cover changes caused by increasing human disturbances. Using the strategic inventory data from the 2005-2006 US Department of Agriculture Forest Service Forest Inventory and Analysis program and other data such as forestland cover and transportation coverage/layers, we modeled the regional patterns of IPs by using a combination of nonparametric techniques, including classification and regression tree analysis, kernel density smoothing, and bootstrapping. For the Midwest region, a probability map and historical records of human-related introduction of IPs of interest suggests that invasive shrubs, herbs, and grasses were initially introduced into the central (sparsely forested) areas and then spread north and south (densely forested areas), whereas invasive vines spread primarily from the south into other parts of the region. The probability of IPs in densely forested areas (0.1) was one-fifth of that in sparsely forested areas. Shrubs are the predominant IF threat and are distributed across the vast region with the exception of the northern part. Invasive grasses and herbs are most abundant in the central part of the region, and invasive vines are most common in the southern part. Percent forest cover and road proximity (distance to roads) as indicators of anthropogenic disturbances, were the most significant drivers of IF occurrence/abundance. Site factors, including forest productivity and stand biodiversity, were significantly correlated with the occurrence of vines. [ABSTRACT FROM AUTHOR]

Abstract: Although oaks (Quercus spp.) have historically dominated much of the forest land in eastern North America, a great deal of fragmentary and sometimes anecdotal evidence suggests that they have been yielding dominance in recent decades to other, typically more shade-tolerant species. Using FIA data, our work formally quantifies the change in oak abundance in the eastern U.S. during the period of 1980–2008. The results indicate that most areas in the eastern U.S. experienced some decline in oak abundance, but the decrease was not universal either geographically or among species. Declines were especially marked in the Central Hardwood Region, which lost oak abundance on 81% its forested area as measured by importance value (IV). Areas with a high oak abundance were more likely to see a reduction in abundance. Among all 25 species analyzed, eight species decreased significantly in IV while two increased. Both the top two most prevalent white oak species (white oak (Quercus alba) and post oak (Quercus stellata)) and red oak species (northern red oak (Quercus rubra) and black oak (Quercus velutina)) had significant decreases in density and IV. Water oak (Quercus nigra) is one of the red oak species that had a near universal increase of its abundance throughout its native range (83% of area). This study provided a comprehensive quantification of the dynamic of oak species in a regional-wide geographic context, which will provoke forest researchers and managers to revisit the oak decline problem by using knowledge from other regions and other species. [Copyright &y& Elsevier]

Black oak (Quercus velutina Lam.) and scarlet oak (Quercus coccinea Muenchh.)—two major components (44% of total stand basal area) of upland oak forests-ore suffering severe decline and mortality in the Ozark Highlands, Missouri. However, factors influencing their survival (mortality) are not well understood. In this study we quantified how stand and tree-level predisposing factors are associated with survival of black and scarlet oaks. Sixteen-year monitoring data from the Missouri Ozark Forest Ecosystem Project (MOFEP) indicated that overall annual mortality of black and scarlet oaks averaged 2.2 and 1.7%, respectively, three to five limes higher than expected (around 0.5%) for while oak, a common associate. For the first 8 years of the study (1990-1 998), survival roles of block and scarlet oaks were similar. Thereafter, the survival role of black oak declined relative to scarlet oak. Using the classification and regression tree (CART) method we classified black oak and scarlet oak trees into seven and nine risk groups, respectively, that differed significantly in rates of tree mortality. Groups were distinguished based on tree diameter, crown class, and size relative to competitors. An oak decline and mortality hazard index was thus developed as the weighted means of risk group mortality, which can help managers prescribe species-specific silvicultural treatments to help mitigate oak decline and associated mortality. [ABSTRACT FROM AUTHOR]

Effects of a catastrophic blowdown event in northern Minnesota, USA were assessed using field inventory data, aerial sketch maps and satellite image data processed through the North American Forest Dynamics programme. Estimates were produced for forest area and net volume per unit area of live trees pre- and post-disturbance, and for changes in volume per unit area and total volume resulting from disturbance. Satellite image-based estimates of blowdown area were similar to estimates derived from inventory plots and aerial sketch maps. Overall accuracy of the image-based damage classification was over 90%. Compared to field inventory estimates, image-based estimates of post-blowdown mean volume per unit area were similar, but estimates of total volume loss were substantially larger, although inaccessibility of the most severely damaged inventory plots may have depressed the inventory-based estimate. This represents the first application of state model differencing to storm damage assessment. The image-based procedure can be applied to historical archives of satellite imagery and does not require pre-disturbance field inventory data. [ABSTRACT FROM AUTHOR]

The introduction of nonnative invasive species (NNIS) into the United States has had tremendous impacts on the nation's commercial and urban forest resources. Of principal concern are the effects of NNIS on forest composition, structure, function, productivity, and patterns of carbon sequestration. In 2006, the Society of American Foresters commissioned on ad hoc team to prepare a white paper on the effect of NNIS on America's forests. The paper was the genesis of this article, which provides an overview of the impacts of NNIS within the United States and includes recommendations for NNIS policy and management. [ABSTRACT FROM AUTHOR]

This paper reports the results of a study that explores the relationship between farm woodland owners’ stated intentions for owning woodland, and the structure and composition of these woodlands in the states of Illinois, Indiana and Iowa in the upper Midwest of the United States. Data from two sample-based inventories conducted by the USDA Forest Service, Forest Inventory and Analysis (FIA) program were combined for this analysis—the FIA forest resources inventory and the National Woodland Owner Survey (NWOS). We looked for relationships between product value and investment in woodlands, as reflected in volumes and tree quality. We also examined whether measures of diversity reflected specific management focus. Our results partially supported our hypotheses. Woodland-focused ownership reasons were found to have larger volumes and individual tree sizes. We found that a passive woodland ownership reason—that woods were “part of the farm”—generally had lower volumes per hectare. Although we were not able to differentiate between different forest product classes and measures of volume, we did find that those landowners who harvested veneer had more volume than those who harvested for firewood. Woodland owners who salvage-harvested their woodlands—a harvesting reason that is more reactive than proactive—exhibited lower volumes per hectare than those who harvested for more proactive, product-focused reasons. Biodiversity was also found to be related to the ownership focus and harvest intent. Generally, there was lower diversity in overstory species when the woodland was viewed merely as “part of the farm,” when the product harvested was fence posts and when timber was harvested for salvage or land clearing. The small sample size limits our analysis, but we can conclude that focusing the woodland owners on management of their woodlands—regardless of what the specific management goals might be—should increase productivity and biodiversity of those woodlands. [ABSTRACT FROM AUTHOR]

Abstract: Modern forestry has been evolving towards multiple-use of forests and maintenance of biodiversity. Interest in integrating natural forest dynamics into management planning and silvicultural practices has increased as a result of concerns related to biodiversity values and maintaining ecological functions in managed forests. Taking advantage of naturally formed advance regeneration to create a new forest is one way of emulating natural forest dynamics, especially in spruce forests. However, efficient use of advance regeneration requires knowledge about factors influencing their performance. Light is important for growth and for crown, shoot and needle morphology of Norway spruce (Picea abies). Crown morphology varies from a conical and deep crown form in relatively high-light environments to the typical “umbrella” form in the understorey shade. Shoots and needles developed in shade are flatter and experience less self-shading than those developed in more light. Needle orientation is horizontal in shade and more vertically inclined in light. The number of nodal and internodal branches increases with increasing light. Tree shoot characteristics are strongly correlated and highly dependent on growing conditions, particularly light. There is a correlation between shoot and needle mass and other shoot variables of current and consecutive year''s growth. The strongest correlations are between length of the shoot and needle mass of the shoot, and the length of the shoot and number of needles on the shoot. Needle length was not as sensitive to the light environment. However, needle width and thickness increased with canopy openness. This paper presents a review of selected literature on the relationships between different tree variables and ecophysiological factors that influence the response and acclimation of Norway spruce advance regeneration to release. The results indicate that crown, shoot and needle characteristics could reflect the acclimation to light conditions and indicate the performance of advance regeneration after release. [Copyright &y& Elsevier]

Forest fires are a disturbance where the effects can range from benign to extreme devastation within a given ecosystem. The stage of stand development coupled with prior management dictates the amount and composition of potential fuels. Thus, fire policy exerts a strong influence on fire effects. Changes in cultural acceptance and use of fire typically drive fire policy. This linkage is perhaps exemplified by America's 300 year love/hate relationship with this powerful natural force. This article uses the four stages of stand development (stand initiation, stem exclusion, understory reinitiation and old-growth), as described by Oliver and Larson (1996), to present opportunities and constraints to fire use, and management options are suggested. Using a selective review of research in the USA that emphasizes the longleaf pine ecosystem in the south-east, the focus is on three themes presented from the viewpoint of a resource manager trying to attain a specific result. First, some high points in the history of fire in America and its ecological ramifications on the landscape are outlined, using examples to illustrate key concepts of behavior, intensity and periodicity. Secondly, examples are given of how people have sought to exclude fire from the landscape, often with disastrous consequences. Thirdly, the topic of prescribed fire in an ecosystem maintenance and restoration role is touched on. Some challenges associated with reintroducing fire into areas where past fire policy dictated its exclusion are also related. [ABSTRACT FROM AUTHOR]

A higher frequency of increasingly severe droughts highlights the need for short-term measures to adapt existing forests to climate change. The maintenance of reduced stand densities has been proposed as a promising silvicultural tool for mitigating drought stress. However, the relationship between stand density and tree drought susceptibility remains poorly understood, especially across ecological gradients. Here, we analysed the effect of reduced stand density on tree growth and growth sensitivity, as well as on short-term drought responses (resistance, recovery, and resilience) of Scots pine (Pinus sylvestris L.), sessile oak (Quercus petraea (Matt.) Liebl.), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson). Tree ring series from 409 trees, growing in stands of varying stand density, were analysed at sites with different water availability. For all species, mean tree growth was significantly higher under low compared with maximum stand density. Mean tree growth sensitivity of Scots pine was significantly higher under low compared with moderate and maximum stand density, while growth sensitivity of ponderosa pine peaked under maximum stand density. Recovery and resilience of Scots pine, as well as recovery of sessile oak and ponderosa pine, decreased with increasing stand density. In contrast, resistance and resilience of ponderosa pine significantly increased with increasing stand density. Higher site water availability was associated with significantly reduced drought response indices of Scots pine and sessile oak in general, except for resistance of oak. In ponderosa pine, higher site water availability significantly lessened recovery. Higher site water availability significantly moderated the positive effect of reduced stand density on drought responses. Stand age had a significantly positive effect on the resistance of Scots pine and a negative effect on recovery of sessile oak. We discuss potential causes for the observed response patterns, derive implications for adaptive forest management, and make recommendations for further research in this field. [ABSTRACT FROM AUTHOR]

• We stem mapped all >40 cm diameter trees in two large sites (32 ha and 73 ha) • Tree densities tended to be higher on sedimentary soils than on basaltic. • In areas with similar tree densities, spatial patterns were very similar. • Higher density areas had large tree (>10 trees) groups with up 113 trees per group. • Small openings dominated, but most of the open area was within a few large openings. Forest spatial patterns influence many ecological processes in dry conifer forests. Thus, understanding and replicating spatial patterns is critically important in order to make these forests sustainable and more resilient to fire and other disturbances. The labor and time required to stem-map trees and the large plot size (>0.5 ha) needed to study tree spatial patterns have limited our examination of how these patterns change as a function of site conditions and tree densities. We stem-mapped all trees >40 cm DBH within two large relict (minimally logged) pure ponderosa pine study sites on experimental forests at Long Valley (73 ha) on sedimentary soils and Fort Valley (32 ha) on basalt soils in northern Arizona, USA. We also simulated 1,000 4-ha plots from models of each study site incorporating field data parameters. Using cluster analysis and field data, we found that an inter-tree distance (ITD) of 9–11 m best separated single trees and groups within our study sites. Using a fixed 10-m ITD, the more productive Long Valley (LV) site had 62 trees ha−1 and groups of up to 113 trees, compared to the Fort Valley (FV) site, which averaged 41 trees ha−1 and had 22 trees in the largest group. However, the sites differed only slightly in terms of single trees ha−1 (LV 7.3; FV 5.6) and group of tree ha−1 (LV 7.2; FV 8.1). Simulation results indicated that when tree densities are equal, the spatial patterns were very similar between the two sites, suggesting that tree spatial pattern variability is a function of tree densities and only indirectly related to site productivity. As the number of trees increased, the additional trees integrated into existing groups rather than creating new groups. In addition to tree spatial patterns, we quantified gaps (defined as >30 m wide stem-to-stem) and openings (defined as ≥30 m wide stem-to-stem) within the two study sites. Although both sites were dominated by small openings most of the open area was found within a few large openings. Our large plots allowed us to incorporate variability and capture a larger range of tree and openings spatial patterns than have been captured in previous studies to provide insights on spatial heterogeneity that can inform management of this important forest type in North America. [ABSTRACT FROM AUTHOR]

A better understanding of the response of plant growth to elevational gradients may shed light on how plants respond to environmental variation and on the physiological mechanisms underlying these responses. This study analyzed whole plant growth and physiological and morphological properties of needles in young Pinus koraiensis Sieb. et Zucc. trees at thirteen points along an elevational gradient ranging from 750 to 1350 m above sea level (a.s.l.) at the end of a growing season on Changbai Mountain in northeastern China. Sampling and analyses indicated the following; (1) many needle properties of P. koraiensis varied with forest type along the elevational gradient though some needle properties (e.g., intrinsic water use efficiency, concentration of chlorophyll, and leaf mass per area) did not change with elevation and forest types; (2) growth was significantly influenced by both forest type and elevation and growth of saplings in P. koraiensis and mixed broadleaved forests was greater than that in evergreen forests and increased with elevation in both forest types; (3) in P. koraiensis and mixed broadleaved forests, there were significant correlations between growth properties and light saturation point, leaf water potential, mean within-crown humidity, annual precipitation, cumulative temperature (≥5 °C), within-crown air temperature, and atmospheric pressure; while in evergreen forests, the leaf C, leaf P content, net rate of light saturation in photosynthesis, water content of soil, within-crown humidity, annual precipitation, cumulative temperature (≥5 °C), within-crown air temperature, and total soil P content displayed a significant relationship with plant growth. These results may help illuminate how P. koraiensis responds to environmental variation and evaluate the adaptive potential of Pinus koraiensis to climate change. Data presented here could also contribute to the more accurate estimation of carbon stocks in this area and to refinement of a plant trait database. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editor discusses the works and success of the journal.

The article discusses the vision of the "Journal of Forestry."

The article announces the integration of regional applied research into the publishing function of "Forest Science" starting in January 2014.

The article offers the authors' insights on the "Journal of Forestry." They mention that readership of the journal is highly educated and knowledgeable concerning natural resources issues, saying that they do not have time to devote on the materials which are not relevant to what they do. They state the journal amended its manuscript guidance which requires the inclusion of a managerial implications statement in each article published in the journal.

This article comments on the issue of forest inventory and analysis (FIA) and on the state of affairs in sampling and estimation in 1999. While FIA had been around for almost 70 years in the U.S., the national forest inventory program had settled on a common design, goals and procedures while still allowing accommodation of regional needs. Since then, geographic information systems and remote sensing technologies had dramatically advanced. FIA had used these advances to improve stratification, incorporate ancillary data, and create maps of estimates.